Similar to room-temperature curable silicone rubbers, oxyalkylene polymers having a reactive silicon functional group are cured with moisture in the air or the like at room temperature to provide a rubbery product. The resulting cured product has excellent characteristics, e.g., high elongation, strength and adhesion, and thus is useful in such applications as sealants and adhesives.
One of the advantages offered by oxyalkylene polymers having a reactive silicon functional group is that because their backbone chain is composed of an oxyalkylene polymer, the surface of their cured product can be coated with almost all paints in common use. In contrast, silicone rubbers, when cured, provide a water-and oil-repellent surface and coating them with paints is impossible in practice.
However, even a composition of an oxyalkylene polymer that contains a reactive silicon functional group suffers the problem that if the composition contains a plasticizer, the film of an alkyd paint applied to the cured composition will not dry (cure) rapidly enough to justify the commercial use of the alkyd paint on the cured composition. Because of this problem, painters have almost given up in their efforts to coat cured products of oxyalkylene polymers containing plasticizers with alkyd paints.